半连续青霉素发酵过程的计算机模拟

在青霉素发酵动力学的方程基础上，本文对半连续青霉素发酵过程的几种主要工艺 计算机模拟，并就模拟结果进行了性能评价，为工业发酵青霉素提供了玫份参考资料。     

农村电网规划与改造方法研究

本文介绍了农村电网规划的任务和原则、供电电源规划、负荷预测、站点和网架的规划改造及其农村电网规划可靠性分析等理论,具有一定的实际指导意义.     

Effects of angiotensin II on connexin 43 of VSMCs in arteriosclerosis

Objective: To observe the effect of angiotensin II (Ang II) on expression of gap junction channel protein connexin 43 (Cx43) in the proliferation process of vascular smooth muscle cells (VSMCs) during the early stage of arteriosclerosis. Methods: Thirty-two adult male rabbits were randomly divided into 4 groups. Rabbits in Group A were fed common diet while others in Groups B, C, and D were fed high-cholesterol diet. Losartan (10 mg/(kg·d)) and ramipril (0.5 mg/(kg·d)) were added in the diet of Groups C and D, respectively. The animals were sacrificed after 8 weeks and abdominal aortas were removed and dissected. The expression of Cx43 was assayed using RT-PCR and Western Blotting analysis. Results: Cx43 was increased markedly in both protein and mRNA level in Groups B, C, and D fed high-cholesterol diet compared with that in control group (P<0.01). Cx43 level in losartan or ramipril treated groups was higher than that in control group (P<0.01, P<0.05), but lower than that in high-cholesterol diet groups (P<0.05, P<0.01). Conclusion: Cx43 level was upregulated in VSMCs during early atherosclerosis. Losartan and ramipril can inhibit the expression of Cx43.     

Biodegradable intestinal stents: A review

Biodegradable stents are an attractive alternative to self-expanding metal stents in the treatment of intestinal strictures. Biodegradable stent can be made of biodegradable polymers and biodegradable metals(magnesium alloys). An overview on current biodegradable intestinal stents is presented. The future trends and perspectives in the development of biodegradable intestinal stents are proposed. For the biodegradable polymer intestinal stents, the clinical trials have shown promising results, although improved design of stents and reduced migration rate are expected. For the biodegradable magnesium intestinal stents, results of preliminary studies indicate magnesium alloys to have good biocompatibility. With many of the key fundamental and practical issues resolved and better methods for adjusting corrosion resistance and progressing biocompatibilities of magnesium alloys, it is possible to use biodegradable intestinal stents made of magnesium alloys in hospital in the not too distant future.     

Comparison of Aerosol Optical Properties over the Semi-arid Region of Loess Plateau between Dusty and Non-dusty Periods in Winter and Spring

Some field experiments of aerosols had been carried out over the arid and semi-arid regions in China over the past 30 years,but there were little learning of the semi- arid region of Loess Plateau. Using Version 2.0 Level 2.0 dataset from the AERONET (Aerosol Robotic Network) Lanzhon_city site,the aerosol optical properties during dusty and non-dusty periods in winter and sprig when air pollrtion frequently occured most frequently were demonstrated. A comparison of the same parameters between Lanzhou and Beijing for spring was also analyzed. Some new information was gained concerning aerosol optical properties over the semi-arid region of Loess Plateau. The results show that the aerosol properties measured during dusty and non-dusty periods are significantly different at Lanzhon,particularly in spring,and also different from those at Beijing.     

FDTD for plasmonics: Applications in enhanced Raman spectroscopy

The exact electromagnetic enhancement mechanism behind SERS, TERS, HERS and SHINERS is one of the issues focused on in the study of enhanced Raman spectroscopy. The three dimensional finite difference time domain method (3D-FDTD), which is widely used in nanoplasmonic simulations, not only provides us with a powerful numerical tool for theoretical studies of the ERS electromagnetic enhancement mechanism, but also serves as a useful tool for the design of ERS-active systems with higher sensi-tivities and spectral spatial resolution. In this paper, we first introduce the fundamental principles of FDTD algorithms, and then the size-dependent dielectric function of dispersive metallic material is discussed. A comparative study of FDTD and rigorous Mie evaluations of electromagnetic fields in the vicinity of a system of self-similar nanospheres shows an excellent correlation between the two computational methods, directly confirming the validity and accuracy of 3D-FDTD simulations in ERS calculations. Finally, we demonstrate, using a TERS calculation as an example, that the non-uniform mesh method can be more computationally efficient without loss of accuracy if it is applied correctly.     

固－固相变贮热的研究（Ⅲ）──三羟甲基乙烷－三羟甲基丙烷二元系

用ＤＳＣ（差示扫描量热法）研究三羟甲基乙烷ＣＨ３Ｃ（ＣＨ２ＯＨ）３（ＰＧ）和三羟甲基丙烷ＣＨ３ＣＨ２－Ｃ（ＣＨ２ＯＨ）３（ＴＭＰ）二元系的混合物的贮热性能．ＰＧ和ＴＭＰ具有固－固转变特性,其纯组分的转变温度分别为８３℃和５５℃附近．研究结果表明,随着ＰＧ浓度的增加,低温峰变小,高温峰形变大．尤其是在ＤＳＣ测试中当第一次加热至固－固相变转化结束后,冷却至室温,再第二次加热,进行ＤＳＣ测试,发现绝大多数ＰＧ／ＴＭＰ二元系出现明显的唯一峰,且倾向高温峰方向,这表明ＴＭＰ对该体系的低温贮热不利     

三角单元部分电导率分块连续变化点源二维电场有限元数值模拟

为了易于模拟地形和地电体,有限单元被设计为三角单元,考虑到实际中岩石,矿物的物性参数均是变化的,单元内电导率被设计为双线性变化,导出一种点源二维地电断面电位计算的有限元方法,该法首先给出沿走向方向进行傅氏变换后的电位的变分问题,然后用有限元方法进行数值计算,最后通过傅氏反变换 ,求得空间域电场。     

Na_2CO_3·10H_2O－NaAc·3H_2O体系相图

Ｎａ_２ＣＯ_３·１０Ｈ_２Ｏ－ＮａＡｃ·３Ｈ_２Ｏ体系相图李卫萍，胡起柱，阮德水（化学系）关键词相图，十水合碳酸钠，三水合醋酸钠中国分类号Ｏ６４２．４２Ｎａ。ＣＯ。·１０Ｈ。Ｏ及ＮａＡｃ·３Ｈ。Ｏ均具有较高的熔化热［‘ｊ和较适宜的相变温度［’－’］，因...     

三元体系Na_2SO_4-(NH_4)_2SO_4-H_2O中的Na_2SO_4·10H_2O-(NH_4)_2SO_4和Na_2SO_4·10H_2O-(NH_4)_2SO_4·Na_2SO_4·4H_2O多温截面图

本文对Na_2SO_4-(NH_4)_2SO_4-H_2O三元体系中的Na_2SO_4·10H_2O_-(NH_4)_2SO_4(Ⅰ)和Na_2SO_4·10H_2O-(NH_4)_2SO_4·Na_2SO_4·4H_2O(Ⅱ)两个多温截面进行了研究.在(Ⅰ)中有三个四相转熔点:P_1,38wt%(NH_4)_2SO_4,58.8℃;P_2,10.9 wt%(NH_4)_2SO_4,26℃;P_3,39.1 wt%(NH_4)_2SO_4,-16℃.在(Ⅱ)中有两个四相转熔点:P_1,100 wt%(NH_4)_2SO_4·Na_2SO_4·4H_2O,59℃;P_2,23.62 wt%(NH_4)_2SO_4·Na_2SO_4·4H_2O,26.1℃,转熔反应热为180 J/g。